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  <script>
    // 题目1(选做)：const arr=['name','age','hhh','hhh','age','hhh','hhh','hhh']各出现多少次
    // 要求输出一个对象如下：{age: 2,hhh: 5,name: 1}
    const arr = ['name', 'age', 'hhh', 'hhh', 'age', 'hhh', 'hhh', 'hhh']
    const obj = {}
    arr.forEach(item => {
      obj[item] ? (obj[item]++) : (obj[item] = 1)
    })
    console.log(obj);
    // 题目2(必做)：现在两个数组，判断在a中的元素，不在b中 const a = [1,2,3,5] const b=[1,3,5,6] 将在a不在b中的筛选出来
    // 要求：输出一个数组：[2]
    const a = [1, 2, 3, 5]
    const b = [1, 3, 5, 6]

    for (let i = 0; i < b.length; i++) {
      for (let j = 0; j < a.length; j++) {
        if (a[j] === b[i]) {
          a.splice(j, 1)
        }
      }
    }
    console.log(a);
    // 题目3(必做):数组去重(可以用多种方法,至少写一种)1
    // 要求：输出一个数组：[1,2,3,9]11
    const arr2 = [1, 2, 3, 2, 9]
    function fn(arr2) {
      for (let i = 0; i < arr.length; i++) {
        for (let j = i + 1; j < arr2.length; j++) {
          if (arr2[i] === arr2[j]) {
            arr2.splice(j, 1)
            j--
          }
        }
      }
    }
    fn(arr2)
    console.log(arr2);

    // 提交成功，测试
  </script>
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